Apparatus and method for treatment of chemical and biological hazards

ABSTRACT

The present invention relates to a method for the deactivation and/or destruction of hazardous materials such as chemical or biological agents. The invention further relates to apparatus for treating hazardous material and for decontaminating items that may have come into contact with it, the apparatus comprising a treatment vessel or chamber and a light source capable of irradiating a catalyst within the treatment vessel or chamber with a predetermined wavelength of light.

The present invention relates to an apparatus for the treatment ofhazardous materials specifically prions, chemical and biological agents.The invention further relates to a method for using such an apparatus.

The risks associated with contamination caused by chemical andbiological agents of various kinds are well known. Medical equipment andsurgical instruments are required to be sterilised to eliminate agrowing range of infectious agents including more recently prionsimplicated in new variant Creusfeld Jacob Disease (nvCJD). Proteinsexhibit huge variation in structure. However, they are formed in similarways and thus display certain structural elements and characteristicsthat are common. The primary structure of proteins is determined by theamino acid sequence and pendant side groups. The amino acid chains arethen folded to form various secondary structures designated as α-helicesor β-sheets. Secondary structure is determined by the folding of theamino acid chains and interactions between the various side groups.Further associations may also form, depending on the protein'senvironment. For example different hydrophilic and hydrophobic groups orareas within the protein molecule are sensitive to the medium in whichthe molecule may be suspended. The prion protein plays an essential rolein the pathogenesis of a group of sporadic, genetically determined andinfectious fatal degenerative diseases, referred to as prion diseases,or transmissible encephalopathys (TSE's), affecting the central nervoussystem of humans and other mammals. The cellular prion protein isencoded with a single copy gene, highly conserved across mammalianspecies. In prion diseases this protein undergoes conformational changesinvolving a shift from α-helix to β-sheet structure. The structures ofthe proteins, both native and rogue, have been extensively investigated.The one of most interest and immediate impact to humans is the proteinassociated with nvCJD. What is unusual about the protein that isassociated with TSEs is the extreme robustness it exhibits. This isthought to be due its β-sheet structure. Prions are known to survivetemperatures in excess of 300° C. Such proteins thus represent presentparticular problems in terms of their transmission and destruction. ThenvCJD prion is known to have a high affinity for stainless steel andother metals posing significant difficulties for the sterilisation ofmedical equipment, such as surgical instruments. At the same time,considering hazards unrelated to the medical field, chemical andbiological agents, such as those used as weapon materials, posesignificant handling and disposal risks.

For the purposes of the present application, the term “hazardousmaterial” means any organic material that may be inimical to human wellbeing and as such may be classed as a chemical or biological hazard.“Hazardous material” includes, but is not restricted to, viral material,bacterial material, prions, proteins, lipids, chemical and biologicalagents/material with associated organophosphate bases, organic waste orby products associated with pharmaceutical processes and blood products,and further includes all of said agents in isolation and when foundwithin, on the surface of or bonded to other material, instruments orequipment. The term “target material” is used throughout in reference toa “hazardous material” which is to be treated according to the method ofthe invention.

The term “treatment” is used in its broadest form and encompasses thedeactivation and destruction of hazardous material. Relatively minormodifications to the structure or conformation of a particular agent maybe sufficient to render it inactive without the need for the agent to bedestroyed or decomposed into constituent elements.

While some methods for treating such agents are known, these typicallyinvolve the use of reagents which are themselves difficult to handle andwhich have associated safety issues. Fluorine and ozone for example maybe effective in catalysing such processes, but create significanthandling problems and are not suited to use in an open bath apparatus.Furthermore some prior art processes are required to be carried out atvery high temperatures and/or pressures. The apparatus used in suchprocesses is necessarily complex and expensive in light of theassociated handling difficulties.

There remains therefore a need for a method for the deactivation ordestruction of prions, chemical and biological agents, which iseffective, efficient and broadly applicable. There is a particular needfor an apparatus and a treatment method that can be used to sterilise ordecontaminate equipment and instruments that may have come into contactwith hazardous material. The present invention as set out below providessuch an apparatus and a method for its use.

Accordingly, in a first aspect the present invention provides apparatusfor treating hazardous material and for decontaminating items that mayhave come into contact with such material. In its broadest form suchapparatus comprises an operator accessible treatment vessel or chamberand a light source capable of irradiating a catalyst within thetreatment vessel or chamber with a predetermined wavelength.

A first embodiment of the invention provides an apparatus, for batchtreatment of hazardous material, comprising a treatment vessel forholding material to be treated; a light source for irradiating thecontents of the treatment vessel; circulation or agitation means andprogress and/or by-product monitoring means. The treatment vessel maycomprise a ‘glove box’ type lid facilitating manipulation of the bathcontents by an operator. An automatic light source cut-off may beincorporated in order to enhance operator safety.

A second embodiment provides an apparatus comprising a treatment vesselhaving one or more decontamination trays for holding hazardous materialor items to be treated, a light source for irradiating the contents ofthe treatment vessel, medium distribution means for circulating acarrier medium within and/or through the apparatus and by-productmonitoring means.

A third embodiment provides an apparatus comprising a holding tank forholding a carrier medium; a catalyst hopper for holding a catalyst; amixing vessel for mixing the carrier medium and the catalyst; one ormore treatment chambers each having a housing which contains a pluralityof treatment beds and a light source; and a distribution header forcontrolling the flow of carrier medium and catalyst into the treatmentchambers. Preferably, each treatment bed comprises means for inducingturbulent flow within the carrier medium flowing therein.

A second aspect of the present invention provides a method for thedeactivation and/or destruction of hazardous material comprising thestep of irradiating the hazardous material in the presence of a catalystwith light having a wavelength in the range of 310 nm to 400 nm. Themethod of the invention causes sufficient chemical modification of thehazardous material so as to deactivate or destroy it.

Preferably, the catalyst is TiO₂ in either rutile or anatase form andpreferably the method is carried out at ambient temperature (of betweenabout 15 to 35° C.) and pressure (of between about 1 to 5 bar).

The method may be carried out in any water based carrier medium that iscompatible with the target material and catalyst. Preferably the carriermedium is water. Judicious choice of treatment medium is required inorder to ensure reliable and effective treatment. In particular whenconsidering the treatment of objects or instruments contaminated withprions for example the physical characteristics of the apparatus andmethod should facilitate a suitable reaction interface. This involvesconsideration of the composition and viscosity of the carrier medium andthe path-length of the apparatus such that the target material, catalystand photons from the light source are brought together in a mannersuitable to effect treatment. It follows that a medium that isrelatively low in viscosity and has appropriate optical characteristics(over the wavelength(s) of the light source) is desirable. In otherwords, the viscosity must be such as to allow the bringing together ofthe target material and the catalyst and the configuration of theapparatus and the optical characteristics of the medium must allowsufficient transmission of light to the target/catalyst reaction site.

Thus, the present invention provides for the treatment hazardousmaterial such as prions linked with human or animal nvCJD in both aα andβ forms and for treatment of instruments and equipment that may havebeen contaminated with said material. The method, and apparatus forimplementing it, are also applicable to the destruction of chemicalagent material, typically organophosphate based systems, as typified byVX or Sarin, but additionally blistering and choking agents as typifiedby Mustard Gas and Tear Gas. Depending upon the conditions employed, theinvention provides for total destruction of some hazardous material bybreaking it down into its constituent parts, principally carbon dioxide,nitrogen, water and inorganic salts, or alternatively provides forsufficient modification of target materials so as to render theminactive. The invention can also deactivate or destroy many otherbiohazards, viral and bacteriological material, and many commonlyindustrially produced organic materials. Furthermore, the method of theinvention can be employed to decontaminate materials, equipment,instruments and the like which may have come into contact with hazardousmaterial.

The method of the invention represents an efficient means ofdeactivating and/or destroying of hazardous material under mildconditions on a batch basis. Further advantages of the invention aredescribed below.

The various aspects of the invention are described in detail below withreference to the accompanying drawings in which:

FIG. 1 shows a first embodiment of an apparatus according to theinvention;

FIG. 2 shows a second embodiment of an apparatus according to theinvention;

FIG. 3 shows a third embodiment of an apparatus according to theinvention; and

FIGS. 4 and 5 are more detailed views of the treatment chamber of theembodiment shown in FIG. 3.

In the drawings similar reference numerals have been used to designatecomponents common to each of the alternative embodiments.

In its broadest form the invention provides a decontamination method forthe treatment of hazardous material comprising the step of irradiatingthe hazardous material in the presence of a catalyst, with light of asuitable wavelength, to deactivate or destroy the target materialthrough photocatalytic oxidative processes. In general terms, theapparatus of the present invention comprises (i) a treatment chamber inwhich the catalyst and the target material may be irradiated with lightof a suitable wavelength (and energy) and (ii) a light source capable ofproducing the desired wavelength. The light source wavelength andintensity may be adjusted to optimise the process depending upon thenature of the target material and the choice of catalyst. A liquidcarrier, preferably a water based medium, is used to introduce hazardousmaterial into the treatment chamber for irradiation.

Without being bound by theory, the invention is considered to be theresult of an interaction of light energy (photons), the catalyst andwater elements that forms hydroxyl radicals which cleave sections of, orlinks in, molecules of the target material (‘primary effects’). Theaction of UV light contributes directly to the breakdown of targetmaterials through photolysis of molecules present. In conjunction withthe formation of hydroxyl radicals hydrogen peroxide (H₂O₂) is alsoproduced. This oxidising agent assists and speeds the decontaminationprocess cycle. The primary effects of hydroxyl radicals allow secondaryprocesses (such as attack by H₂O₂) to act upon vulnerable parts of themolecules. The ultimate result is the break down of hazardous materialinto simple (safe) moieties, formation of inorganic salts within thecarrier medium and production of off-gases, such as CO₂.

The method of the invention employing highly reactive hydroxyl radicalsand H₂O₂ produced through irradiation of a suitable catalyst can beutilised to oxidise prion proteins decomposing them to NO_(x), CO₂,water and various inorganic salts. Attack on a prion protein molecule bya hydroxyl radical causes selective breakage of multiple bond linkages,thus permanently altering the crucial relationship between amino acidunits and inducing changes to their proper attachment and alignment toeach other (and to associated components such as carbohydrates andpossibly lipids). This effect changes the spatial configuration of theprion protein impacting upon its ability to reproduce properly. It ispossible that even small alterations in the protein composition and/orconfiguration are sufficient to impede biological activity of a prionmolecule. Any alteration in the structural make-up and configurationreduces the resistance of the prion to further oxidative processes, suchas attack by H₂O₂, thus increasing the rate of complete oxidation of themolecule.

Contact between the hydroxyl radical/hydrogen peroxide productioninterface and the target material on the equipment/instruments or thelike, using the water based carrier medium with the catalyst, ismaximised. This may be addressed by ensuring that the catalyst withinthe water carrier is migrated to the interface using suitablecirculation or entraining processes. Minimising the spatial offset inthis manner increases the effects of the short-lived radicals producedupon irradiation. Spatial offset distance is further aided through theuse of small catalytic particulate (3-5 microns).

Prior cleaning of gross material make take place within thedecontamination train, that minimises the volume of material to bedecontaminated, and improves throughput.

Increasing the intensity of irradiation and/or increasing the surfacearea of catalyst irradiated can increase radical production. Additionalcatalyst may be introduced to speed the process and replace catalystextracted from the waste stream.

The catalyst may be any photosensitive material, which allows, throughillumination with light of a suitable wavelength, a reaction with theassociated hazardous material to occur. Suitable catalyst materialsinclude for example TiO₂, TiO₃, ZnO, CdS, CdSe, Sn02, WO₃, Fe₂O₃ andTa₂O₅. An example of a preferred catalyst is TiO₂. Irradiation of thecatalyst produces active sites (on what is in effect a semiconductorsurface) causing water absorbed to the surface to be oxidised. Highlyreactive hydroxyl radicals formed in this manner react with (andultimately decompose) the target material present in the system.

The catalyst may be used in any form that provides suitable contact withthe target material. For example, the catalyst may be dispersed in thecarrier medium or it may be coated onto or mixed with the variousmaterials to be decontaminated or destroyed. A catalyst module such as acolumn or tower coated with catalyst material may be employed.Alternatively, the catalyst may be coated onto internal surfaces of theapparatus, enhancing robustness and self-cleaning capability. Recoveryof the catalytic material for reuse, increasing efficiency of theprocess, may be provided for as described below.

While light in the range of 310 nm to 400 nm is preferred, thewavelength of light employed may vary depending upon the catalyst used,the medium used and the nature of the target material. The wavelength tobe used may be selected based on the absorption characteristics of thetarget material, thus increasing efficiency. As photo-generated hydroxylradicals are the primary agents responsible for thedecontamination/destruction processes various parameters may be changedto optimise the effect upon any given target material. The selectedwavelength may be produced for example using a standard mercury lamp inconjunction with a suitable filter.

The method of the invention degrades target materials ultimatelyreducing them to simple reaction products such as CO₂. The evolution ofCO₂ or any other reaction product can thus be used to monitor the degreeand rate of the process. Suitably off-gas production or target materialbreak down may be monitored using techniques such as Raman spectroscopy,mass spectrometry, in vitro tests or other known techniques appropriateto any particular hazardous material.

Characteristics of the method of the invention are detailed in Table 1,together with comparable data for various prior art methods. The‘efficiency’ values indicate the rate and effectiveness of electrontransfer during the treatment process. TABLE 1 Effi- ciency Output TempPressure Catalyst (eV) Medium toxicity (° C.) (bar) Power TiO₂ 3.34Water Very low <36 <10 Low (present invention) Ag (II)* 1.98 Nitric High˜90 10 High acid Ruthenium* 1.8 H₂SO₄ High ˜90 10 High Chlorination* 1.3Water High ˜40 <10 Low H₂O₂** 2.00 Water Low <36 <10 Low*Indicates prior art process;**Hydrogen peroxide not a catalyst as such - included for comparisonpurposes only.

Prior art methods (other than those detailed in Table 1) includehydrogenation and methods employing molten metals or supercriticalwater. These additional methods all pose significant hazards themselvesdue to the operating conditions required in order to be effective (forexample, all three require temperatures in excess of 600° C.; andhydrogenation and supercritical water methods operate at pressures ofabout, or in excess of, 100 bar). Treatment with fluorine, possibly thestrongest oxidising agent known, is also effective, but extremelydifficult and dangerous to handle.

The method of the invention provides an effective and efficient processfor the deactivation and/or destruction of hazardous material, on batchor continuous basis, while overcoming the shortcomings of some prior artmethods in terms of operational requirements and characteristics. Thepresent invention facilitates decontamination treatments to be carriedout under ambient temperature and pressure conditions through a methodand apparatus which has minimal moving parts, is easy to maintain andoperate and which is readily scalable. TABLE 2 Class of CompoundExamples Alkanes Methane; pentane; heptane; n-dodecane; cyclohexane,paraffin Haloalkanes mono-, di-, tri-, and tetrachloromethane;dichloropropane Pentachloroethane; di and tribromoethane;1,2-dichloropropane Aliphatic Alcohols methanol; ethanol; n- andiso-propanol; butanol; penta-1, 4-diol Aliphatic methanoic, ethanoic;Carboxylic Acids trichloroacetic; butyric; oxalic Alkenes propene;cyclohexene Haloalkenes di-, tri- and tetra-chloroethene;hexafluoropropene Aromatics benzene; naphthalene, Tributyl PhosphateHaloaromatics chloro and bromobenzene; chlorobenzenes; halophenolsPhenols phenol; hydroquinone; catecol; resorcinol; cresol, nitrophenolAromatic benzoic; phthalic; salicyclic Carboxylic Acids Polymerspolyethylene; PVC Surfactants polyethylene glycol; p-nonyl phenyl ether;sodium dodecyl benzene sulphonate; paraxon; malathion Herbicides methylviologen; atrazine; simazine; bentazon Pesticides DDT; parathion;lindane, monocrotophos Dyes methylene blue; rhodamine B; methyl orange;fluorescein Explosives Trinitrotoluene Cyanotoxins Microcystins,Anatoxin-a Bacteria E. Coli., Serratia marcescens, Proteins

Table 2 lists compounds successfully destroyed using the presentinvention. Tributyl phosphate, appearing in the ‘Aromatics’ class, is asimulant for nerve agents. TABLE 3 Concentration Wavelength TimeMaterial (% v/v) (nm) (min) Efficiency (%) Methanol 0.1 385 +/− 10 2099.5 Paraffin 0.1 385 +/− 10 40 99.75 Benzene 0.1 380 +/− 10 60 99.9

Table 3 details a number of test materials and the conditions underwhich they were treated. In each case treatment was carried out atatmospheric pressure and at room temperature. The treatment efficiency(which in the case of the three test materials corresponds todestruction of the compounds in question) was measured usingspectrophotometric techniques.

The specific embodiments of an apparatus according to the inventiondescribed below may each be provided with a circulation system, acatalyst feed mechanism, and a catalyst recovery system. In additionthere may be a flushing mechanism to remove excess free catalystdeposits from the cleaned instruments or tools and materials prior tofinal removal and drying. Larger units having the same basic unitstructure may be complemented by material towers coated with thecatalyst through which the contaminated material in the water-basedmatrix is allowed to percolate, thus increasing exposure of thecontaminants to the catalyst and UV sources.

Prior cleaning of gross material make take place within thedecontamination train, that minimises the volume of material to bedecontaminated, and improves throughput.

A first embodiment of an apparatus according to the invention is shownschematically in FIG. 1. The apparatus comprises a treatment chamber orbath (1), a light source (2), a circulation pump (3), an off-gasmonitor/treatment unit (8), a catalyst recovery system (4) and a holdingtank (S). A catalyst hopper (6) and a medium storage unit (7) forstoring the catalyst and carrier medium prior to use are also provided.This first embodiment has been designed for small quantity throughputof, for example, surgical instruments for decontamination or fordestruction of small quantities of target material. Manual manipulationof items in the treatment chamber may be facilitated through use of aglove-box type lid (9). This apparatus is designed for operation bymedical staff in for example medical or dental practices.

Catalyst material and carrier medium are introduced into the holdingtank (5), from the catalyst hopper (6) and the medium storage unit (7)respectively, and from there into the treatment chamber (1). Thecatalyst is typically suspended in the carrier medium and suitablestirring means may be provided in order to ensure that suspension ismaintained and that the suspension circulates within the chamber (1).The contaminated equipment or target material (not shown) is placed into the bath; the lid closed and interlocks (not shown) engaged beforethe process commences. In order to maintain the catalyst in suspensionwithin the carrier medium during the process, the medium is circulatedthrough the system by using suitable means. This facilitates maximumirradiation of the catalyst simultaneously allowing the catalystparticles to contact the interface with the target material. Acirculating pump (3) is used for the removal of catalyst via thecatalyst recovery system (4) at the end of the process run. The catalystrecovery system (4), typically takes the form of a cyclone separator.The level of catalyst in the system is monitored via the processcontroller (not shown) and adjusted to the required level. The carriermedium is circulated within the bath (1) during thedecontamination/destruction process and may be replaced or replenishedfrom the medium storage unit (7) or via the catalyst recovery system(4). The process controller (not shown) is used to monitor the overallprocess, including monitoring off-gas production within the off-gasmonitor/treatment system (8). The off-gas monitoring system (8) providesthe means by which the primary process status is monitored. Thedestruction of organic elements produces CO₂, when no further CO₂production is detected the treatment process may be regarded ascomplete. The residual CO₂ given off is collected by use of an activecharcoal filter fitted into the off-gas system (8). Sampling can befacilitated in order to allow for conformity in vitro testing,spectroscopic analysis or the like to take place. Once completion of theprocess has been confirmed the used carrier medium can be disposed of ina recognised manner and the apparatus may be flushed with fresh medium.The flushing process enables all the areas within the apparatus that mayhave been contaminated by target material to be cleaned, although thesystem is inherently self-decontaminating. The carrier medium withintreatment chamber (1) is then topped-up prior to next usage and themedium in the holding tank (7) replaced. While the method of theinvention may generally be carried out at, or close to, atmosphericpressure, materials may be passed through the apparatus under higherpressure particularly during catalyst recovery and/or cleaning stages.

Access to the treatment chamber (1) for this activity may be provided bya glove box lid arrangement (9). This allows for function (ifnecessary), dismantling and scrubbing of instruments or equipment toremove stubborn or hidden contaminants. These are subsequentlycirculated and destroyed in the treatment chamber during the treatmentprocess. Safety interlocks may be employed to minimise any risks topersonnel during operation, particularly when introducing targetmaterial in to the apparatus. Switching means are provided fordeactivating the light source automatically when the bath lid (9) isopened.

Prior cleaning of gross material make take place within thedecontamination train, that minimises the volume of material to bedecontaminated, and improves throughput.

A second embodiment is shown schematically in FIG. 2. This apparatus isdesigned for use in hospitals or larger clinics with high throughput ofsurgical instruments for decontamination. It is designed for operationby dedicated staff with training in the decontamination of surgicalinstruments and equipment.

The apparatus comprises a treatment chamber (1) having decontaminationtrays (10) an ultraviolet light source (2) and a medium distributionsystem (11). Catalyst from the catalyst hopper (6) and/or a catalystrecovery system (4) are introduced into a holding tank (5). Thecontaminated equipment or product is placed in the decontamination trays(10) and the trays (10) are lowered into the treatment chamber (1). Thelid is closed and interlocks engaged before the process is allowed tostart. In order to maintain the catalyst in suspension within themedium, the medium is circulated by means of a circulation pump (3) anda medium distribution system (11) having a plurality of rotating sprayheads (not shown). The distribution system (11) creates a pressure jeteffect that develops a catalyst laden mist or aerosol within thetreatment chamber (1) which facilitates optimum contact/interactionbetween the UV light, catalyst and target material on the contaminatedinstruments. The carrier medium drains to the bottom of the treatmentchamber (1) where it is collected in a circulation header tank (12)which in turn feeds the circulation pump (3). At the end of thetreatment process any excess catalyst is recovered from the medium via acatalyst recovery system (4). As described above, a process control (notshown) is provided to monitor progress of the treatment by means ofoff-gas monitor/treatment system (8). Upon completion of the treatmentprocess, the lid is removed, trays raised and the decontaminatedinstruments removed.

The medium, including suspended catalyst, may be circulated directlythrough the treatment chamber (1) from the holding tank (5) during thedecontamination process or via the catalyst treatment unit (4) duringthe catalyst recovery cycle. Carrier medium is sampled forconformity/quality maintenance as described in relation to the previousembodiment. The medium level within the circulation header tank (12) ismonitored prior to and during operation and is topped-up as required.

The third embodiment, shown schematically in FIG. 3 with details of thetreatment chamber arrangement shown in FIGS. 4 and 5, is designed foreither high or low volume destruction of high level bio-hazards such aschemical or biological agent materials, prion contaminated material orthe like (and may be adapted to handle solid, liquid or gas phasehazardous materials). It is envisaged that such a system would beoperated in a restricted area by dedicated and suitably trained staff.

The apparatus comprises a series treatment chambers (1) the number andconfiguration of which may be adapted depending upon the nature andquantity of material to be treated. The target material in a suitablepre-prepared state is introduced from a target material hopper (13)under control of metering means (14) into a mixing vessel (15). Thecarrier medium is fed in to the mixing vessel (15) from the circulationheader tank (12) by the circulation pump (3) and catalyst is added froma catalyst hopper (6). The pre-treatment preparation of the targetmaterial may include but need not be limited to the breaking down ofsolids into smaller particles, the suspension of solid particles in aliquid or the absorption of a gas into a liquid. The target material,medium and catalyst mixture cascades into distribution header (16) fromwhich it enters the treatment chambers (1). This method of controllingthe flow of the mixture removes any potential pressure other than thehydrostatic head determined by the relationship between the mixingvessel (15) and the distribution header (16). Each treatment chamber (1)comprises a housing that contains a series of tray-like treatment bedsand a light source (2). The treatments beds are designed to maximise thetime which the carrier medium, catalyst and target material mixture isexposed to the UV light, as well as promoting the formation of turbulentflow. Typically each treatment bed comprises of a series of channels(17) running back and forth across the bed, each channel (17) containinga textured surface (18) designed to induce turbulent flow within themixture. Control of the flow in this manner prevents the catalyst andtarget material from being shielded (as could occur in a laminar flowsituation) and maximises irradiation effectiveness. The treatment bedsare configured with a light source (2), optionally shrouded with amirror, directly overhead. Each treatment bed further comprises atransparent top plate, typically made from quartz or some other materialhaving suitable light transmission characteristics. The treatmentmixture is circulated around the system until the process has beencompleted or for a suitable duration as dictated by the operator. Anysuspended solids, catalyst and other waste products are removed via acatalyst/waste treatment system (4) for storage prior to final disposal.

Specific modifications may be introduced into the carrier mediumcomposition and flow control in order to create the necessaryenvironment for the target material to be suspended within the medium.For example, rotary, ultrasonic or other stirring/agitation means makebe incorporated into the apparatus.

The process is controlled using a suitable process monitoring andcontrol system. This includes monitoring the off-gas status by means ofan off-gas monitoring/treatment system (8). The off-gasmonitoring/treatment system (8) also provides a means for the monitoringand collection/treatment of gaseous reaction products such CO₂, NO_(x),SO_(x) and the like. In order to treat these off-gases specificequipment such as scrubbers and absorbers may be provided. As beforesuitable analytical techniques can be employed to monitor the course ofthe treatment and the content of used waste products and used carriermedium.

The invention is not limited to the embodiments herein described whichcan be varied in construction and detail.

1. Apparatus for the treatment of hazardous material and decontaminationof items contaminated with such material comprising an operatoraccessible treatment vessel adapted to hold said hazardous material orcontaminated items and a light source capable of irradiating contentswithin the treatment vessel with a predetermined wavelength of light. 2.Apparatus according to claim 1 wherein the treatment vessel comprises atleast one tray for holding the hazardous material or contaminated items,and distribution means for circulating a carrier medium within orthrough the apparatus.
 3. Apparatus according to claim 1, furtherincluding monitoring means.
 4. Apparatus according to claim 1 furtherincluding a holding tank capable of holding a carrier medium, a catalysthopper capable of holding a catalyst, a mixing vessel facilitatingmixing of the carrier medium and the catalyst, wherein the treatmentvessel comprises at least one treatment chamber each having a housingcontaining a plurality of treatment beds and a light source, and adistribution header for controlling the flow of carrier medium andcatalyst into the treatment chambers.
 5. Apparatus according to claim 4wherein each treatment bed comprises means for inducing turbulent flowwithin the carrier medium.
 6. A method for treatment for hazardousmaterial or decontamination of items contaminated with such materialcomprising the step of irradiating said material or said items in thepresence of a catalyst with light having a wavelength in the range offrom 310 to 400 nanometres.
 7. A method according to claim 6 wherein thecatalyst is TiO₂.
 8. A method according to claim 7 wherein the catalystis TiO₂ in either rutile or anatase form.
 9. A method according to claim6, wherein the irradiation step is carried out at a temperature ofbetween about 15° C. to 35° C. and a pressure of between about 1 bar to5 bar.
 10. A method according to claim 6, wherein the irradiation stepis carried out in an aqueous based carrier medium.